What is not a microservice?

Async operations with queue (and other) systems

Having 50 different queue consumers (for notifications, logging, reconciliation services, e-mailing etc) doesn’t mean you have 50 microservices

 

Multiple programs running on a single machine and communicating over HTTP

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What is a microservice?

If you are breaking down the fulfillment of a client request into multiple collaborating services that run in their own memory space, then you are doing microservices.

 

THE BASELINE

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Microservices ctd.

Bounded contexts in domain driven design (at worst)

Request–response flow breakdown with

preferably many smaller pieces (with separate codebase)

A bug in a service doesn't bring down the whole app

Scales well, needs minimal additional resources

Supports event-driven architecture

Single responsibility, API interface

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Best practices

Clear interfaces between services

Auto discovery

Dynamic (or zero) configuration

High availability

Scale and update single services

Favor cattle over pets

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Pitfalls

Wrong domain model

Error handling & circuit breaking

Fault-tolerance

Monitoring

Multiple points of failure

Hard to get the big picture

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CHANGE

is the essence of the game

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Code will rapidly change
 

Dependencies will change
 

Deployment & release processes will change
 

What will change?

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Mindset changes

Prepare for and own the change

Defer responsibilities

Increase visibility on dependencies and interfaces between software components

Architectural documents are back

DevOps movement

Integration tests are a lot more important

Controversy: decrease unit and functional tests and increase automated user acceptance tests.

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Benefits

Increase in code ownership
Awareness of impact
Increase in communication
Reduced stress due to automation
Architecture is straightforward; reduces ambiguity for what implementation belongs in what class
DDD is more important, more straightforward

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Infrastructural changes

Freedom to use the best tool for the job

Invest in a solid CI/CD process

Pipelined builds with several stages

Containerize your application

Invest heavily in monitoring

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Benefits

No vendor lock in

No secret sauce

No surprises

Migration is damn easy

Adopting new technologies is lightning fast

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Organizational changes

Team structure completely changes

Scrum teams will get an update

Release management becomes a first-class citizen

Hierarchy is eliminated

Find other ways to keep a consistent vision within the team

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Benefits

Increased agility

Smaller teams lead to easier decisions

Helps with planning for impediments and dependencies; “blocked-by hell”

Increased happiness

Increased productivity

Fit for distributed teams!

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